The present invention is directed to an apparatus for producing fiber material or the like with a prescribable feed weight. The apparatus includes a conveyor means for delivering fiber flocks to a filling stack that comprises a vibrating wall extending in a vertical direction and a displaceable wall, said apparatus including a stationary haul-off drum being arranged in an outlet region of the filling stack, and the haul-off drum supplies the emerging fiber material to a delivery table.
An apparatus as described hereinabove is often referred to as a "vibrating stack feeder" will compress the initially flaky or fuzzy fibers. After the fibers have been compressed in the desired way, they are supplied, for example, to a fleece-forming system.
In a known vibrating stack feeder, the fiber flocks are conveyed from a material box via an ascending spiked lattice and are stripped therefrom with the assistance of stripper drums and then are supplied to a filling stack or vibrating stack, which comprises a vertically residing vibrating wall and a movable wall lying opposite to the vibrating wall. The fiber flocks are, thus, compressed between the two walls. The movable wall is manually adjustable for defining the width of the stack. A stationary pressure roll is provided at the outlet of the filling stack, and this pressure roll will deposit the compressed material onto a delivery table. Subsequently, the fiber material is supplied to an electronic scale. The vibratory motion of the vibrating wall is effected with the assistance of an eccentric drive, whereby the vibrating wall moves essentially parallel between two final positions.
An important characteristic quantity for the quality of the emerging fiber material is the feed weight. In known vibrating stack feeders, this is controlled by the height of the material column in the stack, by the width of the stack, by the vibratory frequency, by the haul-off rate of the conveyor table, as well as the draw-in rate of a following carding means. However, a direct measured quantity can also be established by an intervening scale, for example an electronic scale. The height of the material column in the stack is, thus, also dependent on the conveying speed of the fiber flock, which will be ultimately dependent on the speed of the spiked lattice.
This known way of setting the feed weight via a plurality of parameters is relatively imprecise and subject to inertia, so that a constant quality of the fiber material cannot be guaranteed.